This invention relates to a process for preparing symmetrical ethers.
Many methods are known for preparing symmetrical ethers. Typical references include Houben Weyl, 6/3, pp. 26-30 (1965) and The Chemistry of the Ether Linkage, edited by Paul Patai, Interscience Publishers, 1967. The former reference teaches (at pp. 26-27) that symmetrical ethers are prepared by reacting an alkylating agent with an excess of anhydrous alcohol in the presence of a base, while the latter reference teaches (at pp. 446) that said ethers are formed by the reaction of an alcohol with an alkyl halide in liquid ammonia and, alternatively, by the dehydration reaction of alcohols in acid (at p. 457). Both Houben Weyl (at pp. 28-30) and Patai (at p. 446) teach that said ethers are formed by the reaction of a preformed alkali metal alkoxide with an alkylating agent in a dry inert solvent.
The use of quaternary salt catalysts in the production of symmetrical ethers is also known. A. W. Herriott and D. Picker (Tet. Lett. 44, p. 4,521 (1972)) teach that the reaction of 1-bromooctane with 2N sodium hydroxide in the presence of a quaternary ammonium salt catalyst produces di-n-octyl ether in 75% yield. R. D. Gordon (U.S. Pat. No. 3,824,295) also teaches that the reaction of an alkyl halide, sulfate or sulfonate with aqueous caustic in the presence of a quaternary salt catalyst produces a symmetrical ether.